The paper addresses a problem of optimal staffing in open shop environment. The problem is to determine the optimal number of operators serving a given number of machines to fulfill the number of independent operations while minimizing staff idle. Using a Gantt chart presentation of the problem it is modeled as twodimensional cutting stock problem. A mixed-integer programming model is used to g...

In the multi-operation scheduling that arises in industrial engineering, each job contains multiple tasks (operations) that require execution in different shops. It is assumed that in each shop there is only one machine to perform the required operations. In this paper, a parallel model of multi-operation scheduling is proposed, in which multiple machines are available in each shop to perform t...

in some industries as foundries, it is not technically feasible to interrupt a processor between jobs. this restriction gives rise to a scheduling problem called no-idle scheduling. this paper deals with scheduling of no-idle open shops to minimize maximum completion time of jobs, called makespan. the problem is first mathematically formulated by three different mixed integer linear programming...

This research introduces three heuristic algorithms for solving job-shop scheduling problems, job-shop scheduling problems with multi-purpose machines, and open-shop scheduling problems. All these algorithms are based on the particle swarm optimization algorithm, and generate solutions that belong to the class of parameterized active schedules via their specific decoding procedures. Comparison ...

We consider the open shop, job shop, and ow shop scheduling problems with integral processing times. We give polynomial-time algorithms to determine if an instance has a schedule of length at most 3, and show that deciding if there is a schedule of length at most 4 is N P-complete. The latter result implies that, unless P = N P, there does not exist a polynomial-time approximation algorithm for...

The Open-Shop Problem is a hard problem that can be solved using Constraint Programming or Operation Research methods. Existing techniques are efficient at reducing the search tree but they usually do not consider the absolute ordering of the tasks. In this work, we develop a new propagator for the One-Machine Non-Preemptive Problem, the basic constraint for the Open-Shop Problem. This propagat...

We investigate the multiprocessor multi stage open shop scheduling problem In this variant of the open shop model there are s stages each consisting of a number of parallel identical machines Each job consists of s operations one for each stage that can be executed in any order The goal is to nd a non preemptive schedule that minimizes the makespan We derive two approximation results for this N...

This paper presents a state of the art overview on Ants Systems. Initially the work proposes the fundamental concepts of Ants Theory and offers a description of the main algorithms (based on Ants Theory) and the respective fields of application. Among different fields of application, the paper focuses on industrial plants scheduling problems in open shop, flow shop and job shop systems. The las...

This paper aims to prove the efficiency of an adapted computationally intelligence-based behavior of cats called the cat swarm optimization algorithm, that solves the open shop scheduling problem, classified as NP-hard which its importance appears in several industrial and manufacturing applications. The cat swarm optimization algorithm was applied to solve some benchmark instances from the lit...